Induction heating devices and methods for controllably heating an article

ABSTRACT

A heating device for controllably heating an article defines a processing chamber to hold the article and includes a housing and an EMF generator. The housing includes a susceptor portion surrounding at least a portion of the processing chamber, and a conductor portion interposed between the susceptor portion and the processing chamber. The EMF generator is operable to induce eddy currents within the susceptor portion such that substantially no eddy currents are induced in the conductor portion. The conductor portion is operative to conduct heat from the susceptor portion to the processing chamber. The heating device may further include a platter and an opening defined in the conductor portion, wherein the opening is interposed between the susceptor portion and the platter.

FIELD OF THE INVENTION

[0001] The present invention relates to methods and apparatus forcontrollably heating an article and, more particularly, to methods andapparatus for induction heating.

BACKGROUND OF THE INVENTION

[0002] Silicon carbide (SiC) is increasingly recognized as an effectivesemiconductor material for electronic devices. SiC possesses a number ofproperties that make it particularly attractive for applicationsrequiring devices to operate at high temperature, power and/orfrequency. SiC exhibits highly efficient heat transfer and is capable ofwithstanding high electric fields.

[0003] It has been demonstrated that hot-wall chemical vapor deposition(CVD) reactors can provide epitaxial layers of SiC with morphology anddoping superior to cold-wall systems. See, for example, U.S. Pat. No.5,695,567 to Kordina et al., the disclosure of which is herebyincorporated herein by reference. In certain processes, such asepitaxial growth processes, management of the thermal profile in thevicinity of the substrate may be of great importance. Temperaturegradients may dramatically influence many growth parameters and thequalities of the resulting layers. Where the substrate is disposed on aplatter (e.g., for rotation) separate from a surrounding susceptor andinduction heating is employed, the platter may be significantly coolerthan the internal surfaces of the susceptor. More particularly, thesusceptor may be directly heated by an RF field while the platter isonly or predominantly heated by thermal conduction and radiation fromthe susceptor. The substrate may be cooler even than the platter. As aresult, a substantial thermal gradient may be manifested between thesubstrate growth surface and the internal surfaces of the susceptor. Thethermal gradient may be further exacerbated by the cooling effect of aprocess gas flow through the susceptor.

[0004] The aforementioned temperature gradient may present a number ofproblems. Such problems may include the formation of loose deposits(e.g., SiC) on the hot susceptor wall. Such deposits may fall onto thesubstrate and be incorporated into the epilayers. Moreover, temperaturegradients may cause difficulty in controlling material properties as aresult of non-controllable variations in the temperature gradient andthe narrowing of process windows.

[0005] The foregoing problems may also be presented in other types ofprocesses such as other types of deposition processes and annealingprocesses.

SUMMARY OF THE INVENTION

[0006] According to embodiments of the present invention, a heatingdevice for controllably heating an article defines a processing chamberto hold the article and includes a housing and an EMF generator. Thehousing includes a susceptor portion surrounding at least a portion ofthe processing chamber, and a conductor portion interposed between thesusceptor portion and the processing chamber. The EMF generator isoperable to induce eddy currents within the susceptor portion such thatsubstantially no eddy currents are induced in the conductor portion. Theconductor portion is operative to conduct heat from the susceptorportion to the processing chamber. The heating device may furtherinclude a platter and an opening defined in the conductor portion,wherein the opening is interposed between the susceptor portion and theplatter.

[0007] According to embodiments of the present invention, a housingassembly for an induction heating device defines a processing chamberand includes a susceptor surrounding at least a portion of theprocessing chamber. A thermally conductive liner is interposed betweenthe susceptor and the processing chamber. The liner is separately formedfrom the susceptor.

[0008] The susceptor may include a platter region and the housingassembly may further include: a platter adapted to support the articledisposed in the processing chamber and overlying the platter region; andan opening defined in the liner and interposed between the platterregion and the platter.

[0009] According to method embodiments of the present invention, amethod for controllably heating an article includes positioning thearticle in a processing chamber. An electromagnetic field is applied toa housing about the processing chamber such that eddy currents areinduced within an outer, susceptor portion of the housing and such thatsubstantially no eddy currents are induced in an inner, conductorportion of the housing. Heat is conducted from the susceptor portion tothe processing chamber through the conductor portion.

[0010] Objects of the present invention will be appreciated by those ofordinary skill in the art from a reading of the figures and the detaileddescription of the preferred embodiments which follow, such descriptionbeing merely illustrative of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011]FIG. 1 is an exploded, perspective view of a housing assemblyaccording to embodiments of the present invention;

[0012]FIG. 2 is a perspective view of the housing assembly of FIG. 1;

[0013]FIG. 3 is a perspective view of a reactor assembly according toembodiments of the present invention and including the housing assemblyof FIG. 1;

[0014]FIG. 4 is an end view of the reactor assembly of FIG. 3;

[0015]FIG. 5 is a top plan view of a bottom susceptor member forming apart of the housing assembly of FIG. 1;

[0016]FIG. 6 is a side elevational view of the bottom susceptor memberof FIG. 5;

[0017]FIG. 7 is a cross-sectional view of the bottom susceptor member ofFIG. 5 taken along the line 7-7 of FIG. 5;

[0018]FIG. 8 is a cross-sectional view of a top susceptor member forminga part of the housing assembly of FIG. 1 taken along the line 8-8 ofFIG. 1;

[0019]FIG. 9 is a cross-sectional view of a side susceptor memberforming a part of the housing assembly of FIG. 1 taken along the line9-9 of FIG. 1;

[0020]FIG. 10 is a bottom plan view of a bottom liner forming a part ofthe housing assembly of FIG. 1;

[0021]FIG. 11 is a side elevational view of the bottom liner of FIG. 10;

[0022]FIG. 12 is an end view of a rear liner member forming a part ofthe bottom liner of FIG. 10;

[0023]FIG. 13 is a cross-sectional view of the bottom liner of FIG. 14taken along the line 13-13 of FIG. 10;

[0024]FIG. 14 is a bottom plan view of a top liner forming a part of thehousing assembly of FIG. 1;

[0025]FIG. 15 is a side elevational view of the top liner of FIG. 14;

[0026]FIG. 16 is a cross-sectional view of the top liner of FIG. 14taken along the line 16-16 of FIG. 14; and

[0027]FIG. 17 is a cross-sectional view of a platter forming a part ofthe housing assembly of FIG. 1 taken along the line 17-17 of FIG. 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] The present invention now is described more fully hereinafterwith reference to the accompanying drawings, in which preferredembodiments of the invention are shown. This invention may, however, beembodied in many different forms and should not be construed as limitedto the embodiments set forth herein; rather, these embodiments areprovided so that this disclosure will be thorough and complete, and willfully convey the scope of the invention to those skilled in the art.

[0029] With reference to FIGS. 1-4, a housing assembly 100 and a heatingdevice or reactor assembly 10 including the same according toembodiments of the present invention are shown therein. For the purposesof description, the housing assembly 100 has a front end 104A and a rearend 106A (FIG. 2). With reference to FIGS. 3 and 4, the reactor assembly10 further includes insulation covers 16, 18 surrounding the housingassembly 100. An electromagnetic field (EMF) generator 11 is providedincluding an electrically conductive coil 14 surrounding the covers 16,18 and a power supply 12 as discussed in greater detail below. Thereactor assembly 10 serves as a portion of a hot-wall CVD reactor forprocessing substrates 5 (FIG. 1) such as semiconductor wafers using anatmosphere or flow of a processing gas IG (FIG. 2).

[0030] Turning to the housing assembly 100 in more detail, the housingassembly 100 includes a bottom susceptor member 110, a top susceptormember 120 and a pair of side susceptor members 130 joined by pins 139and arranged to form a box that is open at opposed ends. A bottomconductor member or liner 150 is mounted on the bottom susceptor member110. The bottom liner 150 includes a front liner member 154 and a rearliner member 152 which are separable from one another and togetherdefine an opening 156 therebetween. The opening 156 overlies and exposesa platter region 112 on the bottom susceptor member 110. A platter 140overlies the platter region 112 and is received in the opening 156. Theplatter 140 is rotatably centered by a pivot pin 149. A top conductor orliner 160 overlies the platter 140. The top liner 160 is supported byflange portions 163 that are interposed between the top susceptor member120 and the side susceptor members 130 on either side of the housingassembly 100.

[0031] With reference to FIG. 2, the housing assembly 100 defines aprocessing chamber or passage 102 extending fully through the housingassembly 100 and communicating with an inlet opening 104 and an outletopening 106. More particularly, the passage 102 is defined by theinterior surfaces of the bottom liner 150, the top liner 160, the sidesusceptor members 130 and the platter 140.

[0032] Referring to FIGS. 5 and 6, the bottom susceptor member 110includes holes 110A to receive the pins 139 or other fasteners. Theplatter region 112 may be adapted to provide gas driven rotation of theplatter 140, for example, as disclosed in U.S. patent application Ser.No. 09/756,548, titled Gas-Driven Rotation Apparatus and Method forForming Silicon Carbide Layers, filed Jan. 8, 2001, inventors Paisley etal., the disclosure of which is hereby incorporated herein in itsentirety. An annular, upstanding ridge 114 surrounds the platter region112. An upstanding tab 110B is disposed adjacent the rear end of thebottom susceptor member 110.

[0033] With reference to FIG. 7, the bottom susceptor member 110includes a core 115 and a surrounding layer or coating 117. Preferably,the coating 117 completely surrounds the core 115. The core 115 isformed of a material that has high purity, is able to withstand hightemperatures (e.g., having a melting point greater than 1800° C.), haslow chemical reactivity, and has acceptably low electrical resistance.Preferably, the material of the core 115 has an electrical resistivityof no more than about 100×10⁻⁶ ohm-meter. Preferably, the core 115 isformed of graphite (preferably high purity graphite).

[0034] The coating 117 is formed of a material that has high purity, isable to withstand high temperatures (ea. having a melting point greaterthan 1800° C., has low chemical reactivity, and has acceptably lowelectrical resistance). Preferably, the material of the coating 117 hasa resistivity that is less than the resistivity of the core 115. Morepreferably, the material of the coating 117 has a resistivity that is nomore than 20% of the resistivity of the core 115. Preferably, thematerial of the coating 117 has a resistivity of no more than about20×10⁻⁶ ohm-meters.

[0035] Preferably, the coating 117 is formed of SiC or a refractorymetal carbide, more preferably TaC, NbC, and/or TiC. Most preferably,the coating 117 is formed of tantalum carbide (TaC). The coating 117 maybe applied to the core 115 by any suitable method. Preferably, thecoating 117 is a dense, impervious coating. Preferably, the coating 117has a thickness of at least about 10 microns.

[0036] With reference to FIGS. 1 and 8, the top susceptor member 120includes holes 120A to receive the pins 139 or other fasteners. Withreference to FIG. 8, the top susceptor member 120 includes a core 125and a surrounding layer or coating 127. Preferably, the coating 127completely surrounds the core 125. The core 125 may be formed of thesame materials as discussed above with regard to the core 115, with thesame material(s) being preferred. The coating 127 may be formed of thesame materials and in the same dimensions as discussed above with regardto the coating 117, with the same material(s) and dimensions beingpreferred, and may be applied to the core 125 in the manner describedabove.

[0037] With reference to FIGS. 1 and 9, each side susceptor member 130includes holes 130A to receive the pins 139 or other fasteners. Withreference to FIG. 9, the side susceptor member 130 includes a core 135and a surrounding layer or coating 137. Preferably, the coating 137completely surrounds the core 135. The core 135 may be formed of thesame materials as discussed above with regard to the core 115, with thesame material(s) being preferred. The coating 137 is preferably formedof an impervious material. More preferably, the coating 137 is formed ofSiC (preferably dense SiC that is impervious and has a 0% porosity). Thecoating 137 may be applied to the core 135 by any suitable means ormethods. Preferably the coating 137 has a thickness of at least 100microns.

[0038] With reference to FIGS. 10-13, the bottom liner 150 is showntherein with the liner members 152 and 154 separated for clarity. Therear liner member 152 includes an end slot 152B adapted to receive thetab 110B of the bottom susceptor member 110. The rear liner member 152and the front liner member 154 define opposed semicircular recesses 156Band 156A, respectively. Additionally, semicircular, downward facingrecesses 152C and 154C are formed in the liner members 152 and 154 alongthe recesses 156A and 156B.

[0039] With reference to FIG. 13, the rear liner member 152 includes acore 155 and a surrounding layer or coating 157. Preferably, the coating157 completely surrounds the core 155. The core 155 is formed of amaterial that has high purity, is able to withstand high temperatures(e.g., having a melting point greater than 1800° C., has low chemicalreactivity, and has acceptably low electrical resistance). Preferably,the core 155 is formed of graphite. The core 155 may be formed in thesame manner as described above for the core 115. Preferably, the core155 has a thickness of at least 0.15 inch. The core is preferablyadapted to provide a substantially coplanar upper surface with theplatter 140 when in use (i.e., the platter 140 is levitated).

[0040] The coating 157 is formed of a material that has low chemicalreactivity. Preferably, the coating 157 is formed of SiC or a refractorymetal carbide that is compatible with SiC. More preferably, the coating157 is formed of SiC (preferably dense SiC that is impervious and has a0% porosity). The coating 157 may be applied to the core 155 by anysuitable means or methods. Preferably, the coating 157 has a thicknessof at least about 10 microns. The front liner member 154 is constructedin the same manner as the rear liner member 152, and has a core (notshown) corresponding to the core 155 and a coating corresponding to thecoating 157.

[0041] With reference to FIGS. 14-16, the top liner 160 includes holes160A adapted to receive the pins 139 or other fasteners. A wedge portion162 of the top liner 160 extends with increasing thickness in thedirection of the rear end of the top liner 160. The wedge portion 162may serve to gradually decrease the boundary layer of processing gasflowing through the passage and the outlet opening 106 to promotetransfer of reactants to the substrate surface from the processing gas.

[0042] Referring to FIG. 16, the top liner 160 includes a core 165 and asurrounding layer or coating 167. Preferably, the coating 167 completelysurrounds the core 165. The core 165 may be formed of the same materialsas discussed above with regard to the core 155. The coating 167 may beformed of the same materials as discussed above with regard to thecoating 157 and may be applied to the core 165 in the manner describedabove. Preferably, the core 155 has a nominal thickness of at leastabout 0.15 inch.

[0043] With reference to FIG. 17, the platter 140 includes a pluralityof recesses on the upper side thereof adapted to hold the wafers 5. Apin recess 144 for receiving the pin 149 is formed in the lower side ofthe platter 140. The platter 140 includes a core 145 and a surroundinglayer or coating 147. Preferably, the coating 147 completely surroundsthe core 145. The core 145 may be formed of the same materials asdiscussed above with regard to the side wall susceptors 130. The coating147 may be formed of the same materials and dimensions as discussedabove with regard to the coating 137, with the same material(s) anddimensions being preferred, and may be applied to the core 145 in themanner described above. Alternatively, the platter 140 may be formed ofsolid SiC or a solid SiC alloy.

[0044] The insulation covers 16, 18 may be formed of any suitablematerial to thermally insulate the housing assembly 100. Preferably, theinsulation covers 16, 18 are formed of a material having high purity,low chemical reactivity and a thermal conductivity of less than about 2W/m/K in vacuum.

[0045] Suitable EMF generators for the EMF generator 11 include a BIGavailable from Huettinger Electronic of Germany. The coil 14 and thepower supply 12 are electrically coupled such that the power supply 12may provide an A/C current through the coil 14 at a selected frequencyor range of frequencies. Preferably, the power supply 12 is operable toprovide a current through the coil 14 at frequencies of between at least5 kHz and 1 MHz or a subset of frequencies in this range. Preferably,the power supply 12 is operable to provide power in a range of at least20 kW to 150 kW.

[0046] The housing assembly 100 may be assembled as follows. The sidesusceptor members 130 are mounted on the bottom susceptor member 110.The rear liner member 152 is placed on the bottom susceptor member 110such that the tab 110A is received in the slot 152B and the ridge 114 isreceived in the recess 152C. In this manner, the liner member 152 ispositively located and secured in place on the bottom susceptor member110. The front liner member 154 is placed on the bottom susceptor member110 such that the ridge 114 is received in the recess 154C. Prior to orfollowing placement of either or both of the liner members 152, 154, theplatter 140 is placed on the pin 149 over the platter region 112 and inthe opening 156. The top liner 160 and the top susceptor member 120 aremounted on the side susceptor members 130.

[0047] In use, one or more of the substrates 5 are placed in the passage102 on the platter 140. The power supply 12 is operated to provide apower level and frequency of alternating current through the coil in aknown manner to generate an electromagnetic field. The current frequencyis selected such that eddy currents are generated in the susceptormembers 110, 120, 130. The electrical resistances of the cores 115, 125,135 and the coatings 117, 127, 137 convert at least portions of the eddycurrents to heat such that heat is generated in the susceptor members110, 120, 130. However, the current frequency is selected such thatsubstantially no eddy currents are generated in the liners 150, 160 orthe platter 140. Rather, substantially all of the power from the coil 14absorbed by the housing assembly 100 is attenuated by the susceptormembers 110, 120, 130. Preferably, at least 90% of the power isattenuated by the susceptor members 110, 120, 130, more preferably atleast 95%, and most preferably 100%. Accordingly, no or onlyinsubstantial heat is inductively generated in the liners 150, 160 orthe platter 140.

[0048] The heat or thermal energy inductively generated in the susceptormembers 110, 120, 130 is thermally conducted from the susceptor members110, 120, 130 through the liners 150, 160 and the platter 140 to thepassage 102. The substrate 5 is thereby heated by conduction (throughthe platter 140), radiation and convection. Preferably, the substrate 5is heated to a temperature of between about 1400 and 1800° C. Notably,and preferably, the platter 140 directly overlies the platter region 112of the bottom susceptor member 110 without a portion of the liner 150being interposed therebetween. The coatings 157, 167 on the liners 150,160 may provide thermal breaks from the susceptor members 110, 120 tofurther promote thermal uniformity.

[0049] In this manner, the internal surfaces of the housing assembly 100(i.e., the surfaces in fluid communication with the passage 102) aremaintained at a more spatially uniform temperature so that the thermalgradients in the vicinity of the substrate are reduced. Restated, a moreisothermal environment may be created in the passage 102 for thesubstrate 5 such that the temperature of the portion of the housingassembly 100 in contact with the substrate 5 (i.e., the platter 140) isat substantially the same temperature as the other surfaces defining thepassage 102 (i.e., the interior surfaces of the liners 150, 160 and theside susceptor members 130). The substrate 5 may therefore itself besubstantially the same temperature as the surfaces defining the passage102. As a result, the aforementioned problems associated withundesirably large thermal gradients may be reduced. For example, theformation of loose deposits may be eliminated or reduced. The process(e.g., an epitaxy process) may be more accurately controlled.

[0050] During the reacting process, the processing gas IG (FIG. 2) maybe flowed into the passage 102 through the opening 104. The processinggas IG may include precursor gases such as silane (SiH₄) and propane(C₃H₈) introduced with and transported by a carrier of purified hydrogengas (H₂). The processing gas IG passes through the passage 102. As theprocessing gas IG passes through the hot zone generated by the EMFgenerator 11, SiC deposition reactions take place on the substrate 5.The remainder OG of the processing gas exits the passage 102 through theopening 106. Preferably, the processing gas IG is flowed through thepassage 102 at a rate of at least 10 slpm.

[0051] It may be desirable to remove and replace the platter 140. Forexample, it may be necessary to remove the substrate or substrates 5following processing and replace them with new substrates forprocessing. Also, it may be desirable to remove the platter 140 forcleaning or replacement with a new platter. The platter may beconveniently removed by first removing the front liner member 154 andthen removing the platter 140. It may also be desirable to remove eitheror both of the liner members 152, 154. Each of these procedures may beexecuted without disassembling the remainder of the housing assembly 100or removing the housing assembly 100 from the reactor assembly 10.

[0052] The housing assembly 100 may provide for a more efficient,convenient and durable heating device, particularly where TaC is usedfor the coatings 117, 127 and SiC is used for the coatings 130, 140,150, 160. The TaC coatings 117, 127, 137 may serve to reduce thermalradiation losses and prevent or reduce undesirable sublimation of theSiC coatings. The TaC coating in the platter region 112 of the bottomsusceptor 110 may provide a more durable platform for the rotatingplatter 140. The provision of the SiC coatings in fluid communicationwith the passage 102 and in the vicinity of the substrate take advantageof the adherent nature of parasitic SiC deposits to the SiC coatings andthe chemical, thermal, mechanical, and structural similarity of the SiCcoatings and the SiC substrate 5. The SiC coatings 137 on the sidesusceptor members 130 may assist in reducing the heating of the sidesusceptors due to induction heating.

[0053] The provision of liners 150, 160 separately formed from thesusceptor members 110, 120, 130 may allow for extension of the servicelife of the housing assembly 100 as well as reductions in cost of useand downtime. The liners 150, 160 may be cost-effectively replaced whenthey reach the end of their useful service lives without requiringreplacement of the remainder of the housing assembly 100. Moreover, theliner members 152, 154 can be removed for cleaning (e.g., to scrape awayparasitic deposits) without requiring removal of the housing assemblyfrom the reactor assembly 10 or disassembly of the remainder of thehousing assembly 100.

[0054] The design (e.g., dimensions, materials, and/or placement) of theliner or liners may be selected, modified or interchanged to shape orcontrol the temperature gradient in the processing chamber. For example,additional liners may be positioned along the side susceptor members 130or one or more of the liners may vary in thickness or material. Theliners may be integrated (e.g., as a unitary sleeve). The liners may beintegrally formed with the susceptor member or members. Preferably, theliner or liners will include an opening corresponding to the opening 156positioned to receive the platter.

[0055] Liners may be selected or interchanged to obtain desired gas flowcharacteristics. In particular, the top liner 160 may be removed andreplaced with a top liner having a differently shaped wedge portion 162or having no wedge portion.

[0056] While certain embodiments have been described above, it will beappreciated that various modifications may be made in accordance withthe invention. For example, the processing chamber may be closed at oneor both ends rather than providing a through passage 102. Housingassemblies and heating devices according to the invention may be usedfor other types of processes and material systems, as well as in othertypes of deposition systems. In particular, the housing assemblies andheating devices according to the invention may be used for annealingprocesses. Articles other than semiconductor substrates may beprocessed.

[0057] In other embodiments, end insulation may be placed at either orboth ends of the housing assembly 100. The end insulation, if present,may be shaped like a short cylinder of diameter to match the diameter ofthe covers 16, 18. Passages through the end insulation may be providedto permit the process gas IG to flow freely through the processingchamber. The passages in the end insulations may be provided withprotection liners, preferably made of silicon carbide coated graphite,that separate the process gas IG from the end insulation material whichmay contaminate the process gas.

[0058] While preferred embodiments have been described with reference to“top”, “bottom” and the like, other orientations and configurations maybe employed in accordance with the invention.

[0059] The foregoing is illustrative of the present invention and is notto be construed as limiting thereof. Although a few exemplaryembodiments of this invention have been described, those skilled in theart will readily appreciate that many modifications are possible in theexemplary embodiments without materially departing from the novelteachings and advantages of this invention. Accordingly, all suchmodifications are intended to be included within the scope of thisinvention. Therefore, it is to be understood that the foregoing isillustrative of the present invention and is not to be construed aslimited to the specific embodiments disclosed, and that modifications tothe disclosed embodiments, as well as other embodiments, are intended tobe included within the scope of the invention.

That which is claimed is:
 1. A heating device for controllably heatingan article, the heating device defining a processing chamber to hold thearticle and comprising: a) a housing including: a susceptor portionsurrounding at least a portion of the processing chamber; and aconductor portion interposed between the susceptor portion and theprocessing chamber; and b) an EMF generator operable to induce eddycurrents within the susceptor portion such that substantially no eddycurrents are induced in the conductor portion; c) wherein the conductorportion is operative to conduct heat from the susceptor portion to theprocessing chamber.
 2. The heating device of claim 1 wherein at least90% of the power from the EMF generator absorbed by the housing isattenuated by the susceptor portion.
 3. The heating device of claim 1wherein the susceptor portion includes a susceptor core of a firstmaterial and a susceptor coating of a second material.
 4. The heatingdevice of claim 3 wherein the first material is graphite.
 5. The heatingdevice of claim 3 wherein the second material is SiC.
 6. The heatingdevice of claim 3 wherein the second material is selected from the groupconsisting of refractory metal carbides.
 7. The heating device of claim6 wherein the second material is TaC.
 8. The heating device of claim 1wherein substantially all surfaces of the conductor portion in fluidcommunication with the processing chamber are formed of SiC.
 9. Theheating device of claim 8 wherein the conductor portion includes aconductor core of a first material and a conductor coating of a secondmaterial different from the first material.
 10. The heating device ofclaim 9 wherein the first material is graphite.
 11. The heating deviceof claim 9 wherein the second material is a refractory metal carbide.12. The heating device of claim 9 wherein the second material is SiC.13. The heating device of claim 1 wherein: a) the susceptor portionincludes a first susceptor portion and a second susceptor portiondisposed on opposed sides of the processing chamber; b) the conductorportion includes a first liner disposed between the first susceptorportion and the processing chamber and a second liner disposed betweenthe second susceptor portion and the processing chamber.
 14. The heatingdevice of claim 13 wherein the second susceptor portion includes aplatter region, the heating device further including: a platter adaptedto support the article disposed in the processing chamber and overlyingthe platter region; and an opening defined in the second liner andoverlying the platter region and interposed between the platter regionand the platter.
 15. The heating device of claim 14 wherein the secondliner includes first and second liner members disposed on opposed sidesof the platter and each defining a portion of the opening, wherein thefirst and second liner members are separable.
 16. The heating device ofclaim 15 wherein at least one of the first and second liner members isseparable from the second susceptor portion.
 17. The heating device ofclaim 1 including a platter adapted to support the article disposed inthe processing chamber.
 18. The heating device of claim 17 wherein theEMF generator is operable to generate the electromagnetic field suchthat: the electromagnetic field does not induce substantial eddycurrents in the platter; and the platter conducts heat from thesusceptor portion to the processing chamber.
 19. The heating device ofclaim 17 including an opening defined in the conductor portion, whereinthe opening is interposed between the susceptor portion and the platter.20. The heating device of claim 17 wherein the platter is adapted torotate relative to the susceptor portion.
 21. The heating device ofclaim 1 including an inlet opening and an outlet opening in fluidcommunication with the processing chamber.
 22. The heating device ofclaim 21 including a supply of processing gas reactive to heat todeposit SiC.
 23. The heating device of claim 1 wherein the EMF generatoris operable to heat the susceptor portion to a temperature of at least1400° C.
 24. A housing assembly for an induction heating device, thehousing assembly defining a processing chamber and comprising: a) asusceptor surrounding at least a portion of the processing chamber; andb) a thermally conductive liner interposed between the susceptor and theprocessing chamber, wherein the liner is separately formed from thesusceptor.
 25. The housing assembly of claim 24 including: a firstsusceptor portion and a second susceptor portion disposed on opposedsides of the processing chamber; a first liner disposed between thefirst susceptor portion and the processing chamber; and a second linerdisposed between the second susceptor portion and the processingchamber.
 26. The housing assembly of claim 24 wherein the susceptorincludes a platter region, the housing assembly further including: aplatter adapted to support the article disposed in the processingchamber and overlying the platter region; and an opening defined in theliner and interposed between the platter region and the platter.
 27. Thehousing assembly of claim 26 wherein the liner includes first and secondliner members disposed on opposed sides of the platter and each defininga portion of the opening, wherein the first and second liner members areseparable.
 28. The housing assembly of claim 27 wherein at least one ofthe first and second liner members is separable from the susceptor. 29.The housing assembly of claim 24 including means for positively andremovably locating the liner relative to the susceptor.
 30. The housingassembly of claim 24 wherein the liner varies in thickness along atleast a portion of its length.
 31. A method for controllably heating anarticle, the method comprising: a) positioning the article in aprocessing chamber; b) applying an electromagnetic field to a housingabout the processing chamber such that eddy currents are induced withinan outer, susceptor portion of the housing and such that substantiallyno eddy currents are induced in an inner, conductor portion of thehousing; and c) conducting heat from the susceptor portion to theprocessing chamber through the conductor portion.
 32. The method ofclaim 31 wherein at least 90% of the power of the electromagnetic fieldabsorbed by the housing is attenuated by the susceptor portion.
 33. Themethod of claim 31 including passing a flow of processing gas throughthe processing chamber adjacent the article.
 34. The method of claim 33wherein the step of passing the flow of processing gas includes passingthe flow of processing gas through the processing chamber at a rate ofat least 20 slpm.
 35. The method of claim 33 wherein the processing gasincludes a compound selected from the group consisting of SiH₄ and C₃H₈.36. The method of claim 31 wherein the article is a substrate ofsemiconductor material.
 37. The method of claim 36 wherein the articleis a substrate of SiC.
 38. The method of claim 31 including depositingan epitaxial layer on the article while the article is heated by thethermal energy conducted from the susceptor portion to the processingchamber by the conductor portion.
 39. The method of claim 31 wherein thesusceptor portion includes a platter region, and the conductor portiondefines an opening therein, said method further including: positioning aplatter in the processing chamber such that the opening is interposedbetween the platter region and the platter; and placing the article onthe platter.
 40. The method of claim 39 wherein the conductor portionincludes first and second liner portions defining the openingtherebetween, said method further including: removing the first linerportion from the processing chamber; and thereafter, removing theplatter from the processing chamber.
 41. The method of claim 31including placing the article on a platter and rotating the platter andthe article relative to the susceptor.
 42. The method of claim 31including removing the conductor portion from the susceptor portion.